code: def test_compute_num_samples():
      patch_size = np.asarray([5, 5, 5])
      expected_val = 125
      obtained_val = compute_num_samples(patch_size)
      assert obtained_val == expected_val
  
imports: import warnings
  import numpy
  import scipy.special
  from numpy.testing import assert_, assert_equal, assert_raises, assert_array_almost_equal, assert_warns
  from dipy.denoise.localpca import dimensionality_problem_message, create_patch_radius_arr, compute_patch_size, compute_num_samples, compute_suggested_patch_radius, localpca, mppca, genpca, _pca_classifier
  from dipy.sims.voxel import multi_tensor
  from dipy.core.gradients import gradient_table, generate_bvecs
  from dipy.testing.decorators import set_random_number_generator
label_desc: Use image node_id 19 for calling a global function with example usage: test_compute_num_samples() without return types